The present invention relates generally to web splicing assemblies, and more particularly, is directed to a butt splice assembly for a paper web transport apparatus.
In known paper web transport apparatus, there are two rolls of paper that are provided. When one roll nears depletion, the other roll is spliced therewith, so that a continuous web is always produced from the machine. It is known to produce two different types of splicing, namely butt splicing in which the spliced webs are butted up against each other and lap splicing in which the spliced webs overlap each other at the spliced position. Lap splicing is generally less expensive than butt splicing, and therefore, lap splicing is mostly used. However, in some circumstances, it is required to use butt splicing.
In either case, in some situations, it is important to keep the splicing tape on the same side of the continuous web at all times. For this reason, the two rolls are conventionally mounted on two spindles of an indexing mechanism. When one spindle contains the new web to be spliced, the indexing mechanism is in a first position, but when the other spindle contains the new web to be spliced, the indexing mechanism rotates 180.degree. from the first position. This indexing mechanism therefore becomes rather cumbersome to use, particularly when using webs weighing thousands of pounds that have to be rotated and/or having large diameters.
U.S. Pat. Nos. 4,801,342; 4,856,960; 4,892,611; and 4,923,546, all to Wheeler et al, provide arrangements in which the tape is applied to both sides of a butt splice. When the web from the first roll is the running web, the tape is applied first to a first side of the cut portion of the new web. After adherence of the first side of the cut running web thereto, the tape is applied to the second side of the splice by a vacuum roll.
On the other hand, when the web from the second roll is the running web, the tape is applied first to the second side of the cut portion of the new web, that is, opposite to the aforementioned situation. After adherence of the second side of the cut running web thereto, the tape is applied to the first side of the splice by a vacuum roll.
Accordingly, the tape sections are alternately applied to opposite sides of the web. This is fine in the case where the tape is applied to both sides of the web. However, if the tape is to be applied only to one side of the splice, the tape would be applied alternately on opposite sides of the splice.
Further, in the above patents, the anvil against which the cuts are made and which functions as a pressure backing, is stationary.
U.S. Pat. No. 3,939,032 to Taitel et al and U.S. Pat. No. 4,190,483 to Ryan et al, both having a common assignee herewith, also disclose arrangements in which tape is applied to both sides of the splice in alternating fashion.
U.S. Pat. No. 4,492,609 to Blom discloses a very different arrangement with tape-applying cylinders positioned on opposite sides of the web, and which also provides an indexing mechanism for the web rolls.
U.S. Pat. No. 4,526,638 to Clements discloses an arrangement that also uses a turret or indexing mechanism for the rolls. The splicing assembly includes jaws, each of which carries a splicing head.
Finally, U.S. Pat. No. 4,645,554 to Wyser discloses a device that is concerned directly with the application of an adhesive strip that is always applied to the same face of the webs. However, two anvils associated with suction devices for each web are provided, and neither anvil is reciprocable. Rather, the anvils are stationary. Accordingly, a relatively complicated assembly is provided.